Took me a while to figure out how to hook it up and use it. I had wanted to charge my battery but couldn't quite figure out how to do that. It said the battery was less than 1% and then bad. So instead I decided to use the engine start mode and got the car started no problem. I let it run for 30 min. Then shut it off. The tried to restart and it started up, so it did what it was designed to do. Maybe some day I figure out how to use it as a trickle charger but for now as long as it starts up the car, I'm happy.